1. Field of the Invention
The present invention relates to a color image processing method and apparatus, and more particularly, to a color image processing method for retrieving a color feature descriptor used in indexing and searching a color image.
2. Description of the Related Art
Among visual features for describing multi-media contents, color is the most dominant feature. According to conventional color image processing methods, a color histogram is used for expressing the color information of an image. However, the conventional color image processing methods using a color histogram consisting of 1024 bins have drawbacks in that the computational complexity of image processing steps for describing an image is high and much processing time is required.
To solve the above problem, it is an object of the present invention to provide a color image processing method which can reduce the computational complexity and processing time.
It is another object of the present invention to provide a computer readable medium having a program executable by a computer to perform the color image processing method.
It is still another object of the present invention to provide a color image processing apparatus for performing the color image processing method.
A feature of the present invention is embodied by a color image processing method which includes the steps of (a) obtaining color vectors of an input image, (b) classifying the color vectors to obtain dominant colors of the input image and the ratios thereof, and (c) representing the dominant colors and the ratios thereof as a color feature descriptor of the input image.
The color vectors are preferably quantized color vectors and the ratios are preferably percentiles.
The color image processing method may further include the step of (d) combining the quantized color vectors and the color feature descriptor and representing the combination result as the whole image.
Also, before the step (b), there may be further included the step of performing a predetermined filtering process for smoothing of the input image. Alternatively, before the step (b), the method may further include the step of performing a predetermined filtering process for noise removal of the input image.
Also, before the step (b), the method may further include the steps of analyzing the probability of pixels in the filtered image being noisy pixels and applying appropriate weights thereto, and applying a general Lloyd algorithm to the color vectors corresponding to the weighted pixels to perform color quantization.
According to another aspect of the present invention, there is provided a color image processing method for retrieving a color feature descriptor for describing color features of an image, the method including the steps of (a) segmenting an input image into a plurality of regions, (b) obtaining color vectors for the segmented regions, (c) classifying the color vectors to obtain dominant colors of the input image and the ratios thereof, and (d) representing the dominant colors and the ratios thereof as a color feature descriptor of the input image.
The present invention also provides a computer readable medium having program codes executable by a computer to perform a color image processing method for retrieving a color feature descriptor for describing color features of an image, the method comprising the steps of (a) segmenting an input image into a plurality of regions, (b) obtaining color vectors for the segmented regions, (c) classifying the color vectors to obtain dominant colors of the input image and the ratios thereof, and (d) representing the dominant colors and the ratios thereof as a color feature descriptor of the input image.
According to another aspect of the present invention, there is provided a color image processing apparatus for retrieving a color feature descriptor for describing color features of an image, including a color vector retrieving unit for receiving pixel value data of an input image and retrieving color vectors for a predetermined color coordinate system, and a color feature descriptor generating unit for obtaining the percentiles of dominant colors represented by the color vectors when the color vectors are all received and generating and outputting color feature descriptor data containing the information on the dominant colors and the percentiles thereof.
Also, the present invention provides a color image processing apparatus for retrieving a color feature descriptor for describing color features of an image, including a segmenting unit for segmenting an input image into k regions, wherein k is an arbitrary positive integer, and sequentially outputting pixel value data corresponding to the kth region, a color vector retrieving unit for receiving pixel value data of an input image and retrieving color vectors for a predetermined color coordinate system, and a color feature descriptor generating unit for obtaining the percentiles of dominant colors represented by the color vectors when the color vectors are all received and generating and outputting color feature descriptor data containing the information on the dominant colors and the percentiles thereof.